Table 1.
13C NMR isotropic chemical shifts in ppm from tetramethylsilane (TMS) for N. clavipes dragline silk, random coil, and polypeptides with defined secondary structures.
| Residue | N. clavipes | α-Helix | β-Sheet | Random Coil | 31-helix a |
|---|---|---|---|---|---|
| Gly Cα | 43.2 | 46.0 | 43.2–44.3 | 43.4 | 41.4–42.5 |
| Gly CO | 169.7 | 174.9 | 168.4–169.7 | 173.2 | |
| Ala Cα | 49.3 | 52.3–52.8 | 48.2–49.3 | 50.8 | 48.9 |
| Ala Cβ | 50.3 | 14.8–16.0 | 19.9–20.7 | 17.4 | 17.4 |
| 17.4 | |||||
| 20.9 | |||||
| Ala CO | 172.8 | 176.2–176.8 | 171.6–172.2 | 176.1 | 174.6 |
| 174.5 | |||||
| Gln CO | 172.6 | 175.4–175.9 | 171.9–172.2 | 174.3 | – |
| Gln Cα | 52.7 | 56.4–57.0 | 51.0–51.4 | 54.0 | – |
| Gln Cβ | 25.8 | 25.6–26.3 | 29.0–29.9 | 27.7 | – |
| Gln Cγ | 30.6 | 29.7–29.8 | 29.7–29.9 | 32.0 | – |
| Gln Cδ | 176.6 | – | – | 178.8 | – |
| Tyr CO | 172.7 | 176.7 | 169.7 | 174.2 | – |
| Tyr Cα | 55.1 | 54.8–58.6 | 52.1 | 56.2 | – |
| Tyr Cβ | 37.7 | 36.1 | 39.3 | 37.1 | – |
| Tyr Cγ | 128.6 | 129.7 | 128.0 | 128.9 | – |
| Tyr Cδ | 130.9 | 129.7 | 128.0 | 131.6 | – |
| Tyr Cε | 116.1 | 116.1 | 115.0 | 116.5 | – |
| Tyr Cζ | 156.2 | 154.2 | 155.2 | 155.6 | – |
| Leu CO | 176.0 | 175.7 | 170.5–171.3 | 175.9 | – |
| Leu Cα | 53.8 | 55.7 | 50.5–51.2 | 53.4 | – |
| Leu Cβ | 41.6 | 39.5 | 43.3 | 40.7 | – |
| Leu Cγ | 24.0 | – | – | 25.2 | – |
| Leu Cδ | 23.3 | 24.4 | 24.9 | 24.3 | – |
a (AGG)10 model peptide with (φ, ψ) values near (−90°, 150°).